title: Nitrate does not compete with abscisic acid as a substrate of AtNPF4.6/NRT1.2/AIT1 in Arabidopsis.
abstract: We identified a member of the Arabidopsis NRT1/PTR FAMILY (NPF), AtNPF4.6, as an abscisic acid (ABA) transporter, AIT1. AtNPF4.6 was originally characterized as a low-affinity nitrate transporter NRT1.2. We hypothesized that the competition between nitrate and ABA as substrates for AtNPF4.6 might be involved in the interactions between nitrate and ABA signaling. However, the ABA transport activity of AtNPF4.6 was not inhibited by an excess amount of nitrate. In addition, the npf4.6 mutant was less sensitive to ABA than the wild type during germination irrespective of nitrate concentrations in the media. Furthermore, nitrate promoted germination of both wild type and npf4.6 in the presence of ABA. These results do not support the idea of a physiological linkage between nitrate and ABA signals through AtNPF4.6.
authors.affiliation: RIKEN Center for Sustainable Resource Science; Yokohama, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Kanno
authors.affiliation: RIKEN Center for Sustainable Resource Science; Yokohama, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kamiya
authors.affiliation: RIKEN Center for Sustainable Resource Science; Yokohama, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Seo
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D027321:Anion Transport Proteins / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D018525:Germination / Q000187:drug effects; D009566:Nitrates / Q000494:pharmacology*; D010940:Plant Proteins / Q000378:metabolism*; D013379:Substrate Specificity / Q000187:drug effects; D020798:Two-Hybrid System Techniques
chemical_list: D027321:Anion Transport Proteins; C101492:NRT1.1 protein, Arabidopsis; D009566:Nitrates; D010940:Plant Proteins; D000040:Abscisic Acid
keywords: NRT1/PTR FAMILY (NPF); abscisic acid; nitrate; plant hormone; transporter